Such a device is known from EP 0 161 748 B1 (see the exemplary embodiment in accordance with claim 4 and the specification, column 5, line 53). There, the pressure cheek (referred to as an insert there) can be tilted in an axis parallel with respect to the axis of rotation of the workpiece as indicated by the arrow B in FIG. 5. To this end, a pin arranged in a support is passed through the pressure cheek.
The arrangement for turning the workpiece and the means for putting the retaining arms into a back-and-forth movement with respect to the axis of rotation of the workpiece, which are not shown in detail in the present application, are also represented in the mentioned document. It is furthermore pointed out that the retaining arms themselves can perform a pivot movement, which makes it possible for them to follow an eccentric rotating movement of the workpiece, for example, if the latter is constituted by the connecting rod bearing of a crankshaft or cam shaft.
A similar arrangement is described in U.S. Pat. No. 1,905,821, in DE 44 44 239 A1, in the prospectus of 3M company "Imperial Brand Microfinishing Film Roll" (1981) and in the article by Haasis, "Bandfinishing--Ein wirtschaftliches Feinbearbeitungs-verfahren" [Band Finishing--An Economical Fine Machining Process] in "Fachberichte fur Oberflachentechnik" [Special Reports on Surface Technology], 8 (1970) vol. 9/10, pp. 203 to 208. Such band finishing machines additionally have arrangements for moving the grinding belt, as soon as it has been used up, forward over a defined section of length in such a way, that an unused grinding belt section becomes available for finishing the workpiece. Such arrangements are also known from the above mentioned patent documents.
The use of the supports (shoes) and pressure cheeks (inserts) in the prior art in accordance with EP 0 161 748 requires an adjustment of the inserts in relation to the cylindrical workpiece to be finished, or respectively to its surface to be finished (for example the connecting rod bearing surface of a crankshaft). Because of this, the process of changing the insert becomes complicated.
Furthermore, in spite of the desired shape correction by the use of incompressible grinding belts, it is often desired to retain a certain remaining elasticity of the pressure cheeks, so that the latter can be adapted to different initial diameters of the finished surface. This is desired not only for achieving an improvement of the surface and a shape correction, but also a reduction of the diameter to a defined final size. The pressure cheek is supposed to be slightly spread when being placed on a workpiece, whose diameter is greater than the nominal diameter, so that material is taken off until the nominal diameter has been achieved. This relates to the removal of material in the range of a few .mu.m. Thus, within the limits mentioned, a certain amount of elasticity of the pressure cheeks should be assured, which makes possible and simplifies a simultaneous shape correction, surface improvement and working down to a final size (=nominal size).